Jet noise suppressor nozzle



July 12, 1960 F. w. w. MORLEY 2,944,624

JET NOISE SUPPRESSOR NZZLE Filed July 25, 1958 3 Sheets$heet 1 IHHHHIIHHI Inventor &4

A ttorney,

July 12, 1960 3 Sheets-Sheet 2 Filed July 25, 1958 Inventor A ttorney;

July 12, 1960 Filed July 25, 1958 FFW. W. MORLEY JET NOISE SUPPRESSOR NOZZLE 3 Sheets-Sheet 5 Unite States Patent O ice This'invention relatesito. a'jet noise suppressor nozzle. According to the present invention there is provided a jet noise suppressor nozzle comprising'la plurality of individual nozzle members in a spaced arrangement around a' central nozzle member, each nozzle member having within it an internal wall 'member forming "a chamber open at its downstream end, the chambers being closed attheir upstream ends'and having provision for flow of atmospheric air therethrough in a downstream'di'rection, each internal wall member being'positionedrelatively to the inner wall-of its nozzle member'to provide a'longitudinal'cha'nnel 'foi'flow of hot gases therethrough from Preferablya di-viding wall member divides eachichamber 'into an inner compartment surrounded by an outer compartment, the flow ofatmospheric air being arranged: to occur-through the inner compartment. Pressure bal ance" means arepr'efe'rably provided for ensuring that the 1 pressure in the outer compartment is' substantially th same'as that in the said longitudinal channel.

The provision for the flow of atmospheric air into th chambers can be in the formof apertures provided in the walls of theindividual nozzle members.

The individual nozzle members can be-substantially" cylindricaland can be spaced at equal angula r'intervals in a circular arrangement around a central substantially cylindrical nozzle member. V

The internal wall members can be situated at the downstream ends of the nozzle members and the chambers' formed thereby can increase in-radial extent in a downstream direction.

The invention is illustrated, merely .by way of example, in the accompanying drawings'in which:

Figure l is a perspective view of an'ozzle' embodying the invention, part of the nozzle being'broken'away to show the construction more clearly;

FigureZ shows diagrammatically a gas'turbine'engine embodying a nozzle-according to the invention} Figure 3 is a section through the nozzle on=1ine" 3- ofFig'ure 4; i

Figure 4 is a sectionthrough the nozzle on line 4-4 of Figure'3; and r Figure 5 is a perspective, view 'partlybroken away, of

amodified embodiment of anozzle according to the invention.

Referring first to the embodiment of Figures 'l-*-4,' the arrowi'9 indicates the direction of gaseous flow through a-nozzle 10, the nozzle comprisinga central' substantially'cylindrical nozzle member 11 supported by an external nozzle wall member 12 and an internal nozzle wall member 13. The wall members 12 and 13" also end.""-

aperture 17 is provided in the external wall of each nozz'le member 14, the aperture 17 extending throughout the major proportion of the length'of the nou le' member andbeing situated so as to allow air to pass into the interiorof chamber 16 and t'o'pa'ss out through theopen end of the chamber. I

Each wall memben '15- is spaced from the internal wall 18 ofea'ch nozzle member 14 so as to provide'a-longitudinal channel l4a for flow of gases from the jet pipe.

The control'cylindrical nozzle member llalso hasa number offlow-div'iding wall members 19 forming c'ham{ ber-s20 and there are a plurality of apertures 21 adapted to allow air to enter the chambers 20 and-flow out of the opendow'nstrearnends. The wall members 19 are positioned relativelytoeach other and to the inner-wall of thenozz lernemb'er 11 so as to provide a plurality of chainnels :24 for flow of gases from the jet pipe.

The nozzle can be applied toa gas turbine engine 22, as shoyvn' diagrammatically in Figure 2. I

In use jet gases pass out of the jet pipe in the direction of the arrow 9 and are divided by baffle means 8 soas" to flow through the channels 14a and the'cha'nn'els 24'out of thedownstre'am end of the nozzle members. Atmospheric air: enters the chambers 16 through the apertures" 17' and also enters the chambers 20 through the apertures 21'to pass out- 0f the downstream ends of chambers 20,

and to'mix with'gases from the jet'pipe at the boundaries" 7 formed by the downstream edges of the wall members 19.

let gasesfiow' through holes 13 in the wall member 13' into' the 'spac'e'betwe eu wall members 12 and 13 a'swell as thr'oug h'the jet pipe within the-wall member 131'" Accordingly the inwardly bent portion 13a of the wall-menu ber 13 will be 'pr'essu're balanced and need not be of great strength" as itdoes not 'have'to' withstandhigh gas" loads.

The modified embodiment of the invention illustrated in'Figure 'S is generally similar'tothat of Figures 1-4 in that it comprises a' central cylindrical nozzle member ll 'surrounded 'by'seven nozzle' members 14 spaced from each other at equalan'gular intervals, thenozzle"'mem bers'11;14 b'eing respectively provided with" internal 'wall memb ers19, 1 5.' In the Figure 5 construction,"however,' the chambers l'fi formed' byj th'e internal wall members 15 are divided by a wall member 25 into an inner" compartment 26jand anouter compartment 27 'surrouric'lin'g= the inner compartment.

The inner compartment 26 is disposed adjacent the inner wallof the nozzle'member 14 and is; provided with the apert'ures' 17. The wall members 15 and 25"a1'e welded tofeach other "along-lines ofwelding 28. The

-' internal wall'member 15is provided with a number (eg.

support a'nurnber' (e.g..seven) of substantially cylindrical nozzle members 14 disposed at equal angular intervals ina circular arrangement around the central nozzle member 11 (Figures 1, 3 and'4). Eachnozzle member 14 includes an internal wall member 15 forminga chamber 16 open at 'its downstream end and closed at its upstream 4) ofpressure balance holes 29 which ensure that' the" pressurawith in' theoutercompartment 27 is substantially thesame as that of thegases' flowing through the longi-' For'this tudina l channels 14a in the nozzle member. reasonthe wall member '15 need not be a heavy one.

It will be appreciated that in the Figure 5 .const'ructior'r the hot gases' from the jet pipe will not impinge oil/the dividing wall member 25 which may'therefor'e also be oflight construction. Thus the provision of thedivid ing wall member 25 enables the structure ofthe noise suppresser nozzle of the present inventio'n'to be'li'g'htened."

'SimiIarlyeach of the chambers 20 of theceritr'abno'z zle member 11 is'divided' into an inner and an outer-"com: partment by a wall member 30, the outer-earn artinent being pressure balanced with respect to"the"pfe'ssure of the hot gases flowing thto'ughthe channels 24' ""the' central nozzle member 11 by holes 30' extending-through the wall member 19. Here again, the provision of the wall" member 30 enables a lighter structure to be' 'ern'-' ployed.

The wall members 15 and 25 of each nozzle member ---Patented Ju -3' 1960 3 14 are respectively shaped to suit the gas flow and the airflow through the nozzle member 14. Similarly the wall members 19, 30 and the central nozzle member 11 are respectively shaped to suit the gas flow and air flow through the nozzle member 11 although as will be seen from Figure 5, the flow lines of the wall members 19, 30 difier somewhat from those of the wall members 15, 25.

The dividing wall member 25 may be secured to the inner'surface of its nozzle member 14 by argon welding While the wall member 15 is flanged at 15' and may be stitch welded to the inner surface of its nozzle member.

Each nozzle member 14- has a rear section 31 and a forward section 32 which are butt welded to each other along a line The aperture 17 is provided wholly within the rear section 31 and is surrounded by a reinforced plate 34 which'is welded to the outer surface of the nozzle member.

A bafile structure'35 is provided at the junction of each nozzle member 14 with the central cylindrical member 11 so as to ensure that the hot gases are directed positively either into' the central nozzle member 11 or into the nozzle member 14.

The chamber 36 formed by the wall members 12, 13 and bounded by the nozzle members 14 and the central nozzle member 11 is pressure balanced by holes 37 in the wall member 13.

It will be noted that the jet noise suppressor nozzle shown in the drawings comprises nozzle members 11, 14 which are substantially circular in cross section. The entry of the hot gases into the nozzle members 11, 14 and their passage therethrough is, as a result, such that the propulsive efiiciency of the construction shown in the drawings is superior to that of silencers employing conventional corrugated nozzles. The form of the nozzle members 11, 14, moreover, makes for ease and rigidity of construction and, since is makes more efl'lcient use of space, it also enables theoverall size of the silencer to be reduced in comparison with silencers employing corrugated nozzles.

I claim: r

1. A noise suppressor nozzle for use on a jet engine comprising a central nozzle member, a plurality of individual nozzle members in a spaced arrangement around said central nozzle member, an internal wall member in and extending to the downstream end of each of said nozzle members, each said internal wall member being disposed to provide a longitudinal channel in its nozzle member for the flow. therethrough of hot gases from a jet pipe, each said internal wall member forming with the inner wall of its nozzle member a chamber which is open at its downstream endand closed at its upstream end, andimeans providing for flow of atmospheric air through each of said chambers in a downstream direction. 2. A noise'suppressor nozzleforuse on a jet engine comprising a central nozzle member, a plurality of individual nozzle members in a spaced arrangement around said central'no'zzle member, an internal wall member in and extending to the downstream end of each of said nozzle members, each said internal wall member being disposed to provide a longitudinal channel in its nozzle member for the flow therethrough of hot gases from a jet pipe, each- .said internal wall member forming with the inner wall of its nozzle member a chamber Which is open at its downstream end, and closed at its upstream end, a dividing wall member dividing each said chamber into an inner compartment surrounded by an outer compartment, and means providing for flow of atmospheric air through each of said inner compartments in a downstream direction.

3. A noise suppressor nozzle for use on a jet engine comprising a central nozzle member, a plurality of individual nozzle members in a spaced arrangement around said central nozzle member, an internal Wall member in and extending to the downstream end of each of said nozzle members, each said internal wall member being disposed to provide a longitudinal channel in its nozzle member for the flow therethrough of hot gases from a jet pipe, each said internal wall member forming with the inner wall of its nozzle member a chamber which is open at its downstream end and closed at its upstream end, a dividing wall member dividing each said chamber into an imier compartment surrounded by an outer compartment, pressure balance means maintaining the pres sure of the outer compartment substantially the same as that in a said longitudinal channel, and means providing for flow of atmospheric air through each of said inner compartments in a downstream direction.

4. A noise suppressor nozzle for use on a jet engine comprising a central nozzle member, a plurality of innozzle members for flow of atmospheric air through each of said chambers in a downstream direction.

5. A noise suppressor nozzle for use on a jet engine comprising a central nozzle member, a plurality of individual nozzle members in a spaced arrangement around said central nozzle member, an internal wall member in and extending to the downstream end of each of said nozzle members, each said internal wall'membenbeing disposed to provide a longitudinal channel in its nozzle member forthevfiow therethrough of hot gases from a jet pipe, each said internal Wallrnernber forming with the inner wall of its nozzle member a chamber which is open at its downstream end and closed at its upstream end, a dividing wall member dividing each said chamber into an inner compartment surrounded by an outer compartment, and means providing apertures in the walls of the nozzle members for flow of atmospheric air through each of said inner compartmentsin a' downstream direction.

6. A noise suppressor'nozzle toruse' on a jet engine comprising a central nozzle member, a plurality of individual nozzle members in a spaced arrangement around said central nozzle member, means supporting the individual nozzle members from the central nozzle member and forming enclosures between the individual nozzle members and the central nozzle member,- an internal wall member in and extending to the downstream end of each of said nozzle members, each said-internal wall member. being disposed to provide a longitudinal channel in its nozzle member for the flowtherethrough of hot gases from a jet pipe, each said internal wallmember forming with the inner wall .of its nozzle member a chamber which is open at its downstream end and closed at its upstream.

end, pressurebalance means maintaining the pressure in the enclosures substantially the same as the pressure in the said longitudinal channels, and means'providing for flow of atmospheric air through each of saidchambers in a downstream direction.

7. A noise suppressor nozzle 'for use on a comprising a central nozzle member, a plurality .of individual nozzle members in a spaced arrangement around said central nozzle member, ,means'supporting the individual nozzle members from the central 'nozzle memher and forming enclosures between the individual nozzle members and the central nozzle member, an internal wall member in and extending to the downstream end of each of said nozzle members each' said internal wall member-being disposed to provide a longitudinal channel in its nozzle member for the flow therethrough of hot gases from a jet pipe, each said'internal wall memberforming with the inner wall of its nozzle member a jet engine chamber which is open at its downstream end and closed at its upstream end, pressure balance means maintaining the pressure in the enclosures substantially the same as the pressure in the said longitudinal channels, a dividing wall member dividing each said chamber into an inner compartment surrounded by an outer compartment, pressure balance means maintaining the pressure in the outer compartment substantially the same as that in a said longitudinal channel, and means providing for flow of atmospheric air through each of said inner compartments in a downstream direction.

8. A noise suppressor nozzle for use on a jet engine comprising a central nozzle member, a plurality of individual nozzle members in a spaced arrangement around said central nozzle member, an internal Wall member in and extending to the downstream end of each of said nozzle members, each said internal wall member being disposed to provide a longitudinal channel in its nozzle member for the flow therethrough of hot gases from a jet pipe, each said internal wall member forming with the inner wall of its nozzle member a chamber which increases in radial extent in a downstream direction and which is open at its downstream end and closed at its upstream end, and means providing for flow of atmospheric air through each of said chambers in a downstream direction.

9. A noise suppressor nozzle for use on a jet engine comprising a central nozzle member, a plurality of individual'nozzle members in a spaced arrangement around said central nozzle member, an internal wall member in and extending to the downstream end of each of said nozzle members, each said internal wall member being disposed to provide. a longitudinal channel in its nozzle 9 member for the flow therethrough of hot gases from a jet pipe, each said internal wall member forming with the inner wall of its nozzle member a chamber which is open at its downstream end and closed at its upstream end, bafiie means for directing hot gases from a jet pipe selectively into the central nozzle member and into'one of said individual nozzle members, and means providing for flow of atmospheric air through each of said chambers in a downstream direction.

10. A noise suppressor nozzle for use on a jet engine comprising a central nozzle member, a plurality of individual nozzle members disposed at equal angular intervals in a circular arrangement around said central nozzle member, an internal wall member in and extending to the downstream end of each of said nozzle member disposed to provide a longitudinal channel in its nozzle member for the flow therethrough of hot gases from a jet pipe, each said internal wall member forming with the inner wall of its nozzle member a chamber which is open at its downstream end and closed at its upstream end, and means providing for flow of atmospheric air through each of said chambers in a downstream direction.

11. A noise suppressor nozzle for use on a jet engine comprising a central nozzle member, a plurality of individual nozzle members disposed at equal angular intervals in a circular arrangement around said central nozzle member, means supporting the individual nozzle members from the central nozzle member and forming enclosures between the individual nozzle members and the central nozzle member, an internal wall member situated in and at the downstream end of each of said nozzle members and disposed to provide a longitudinal channel in the nozzle member for the flow therethrough of hot gases from a jet pipe, each said internal wall member forming with the inner wall of its nozzle member a chamber which increases in radial extent in a downstream direction and which is open at its downstream end and closed at its upstream end, pressure balance means maintaining the pressure in the enclosures substantially the same as the pressure in the said longitudinal channels, baflle means for directing the hot gases from the jet pipe selectively into the central nozzle member and into one of said individual nozzle members, a dividing wall member dividing each said chamber into an inner compartment surrounded by an outer compartment, pressure balance means maintaining the pressure in the outer compartments substantially the same as that in said longitudinal channels, and means providing apertures in the walls of the nozzle members for flow of atmospheric air through each of said inner compartments in a downstream direction.

References Cited in the file of this patent UNITED STATES PATENTS 

